FIG. 4.

Inhibition of p38 MAP kinase activity decreases R. rickettsii-induced COX-2 expression. (A) Detailed densitometric analysis of COX-2 expression during R. rickettsii infection (Rr) in the presence and absence of a specific p38 MAP kinase inhibitor, SB 203580 (SB80). The results were calculated as means ± standard errors from three independent observations. *, significant reduction (P ≤ 0.05) in COX-2 mRNA level compared to that in infected cells alone, i.e., in the absence of the p38 inhibitor SB 203580. (B) Comparison of the effects of selective inhibition of ERK and p38 MAP kinase pathways via PD 98059 (PD; 10 μM) and SB 203580 (SB80; 10 μM), respectively, on the COX-2 mRNA level in uninfected (C) and R. rickettsii-infected (Rr) endothelial cells.